Final answer:
Myasthenia gravis is an autoimmune disorder characterized by muscle weakness due to the blockage of acetylcholine receptors. A cholinergic crisis in a myasthenia gravis patient can result in decreased blood pressure and constricted pupils.
Step-by-step explanation:
Myasthenia gravis is an autoimmune disorder in which circulating antibodies block the nicotinic acetylcholine receptors on the neuromuscular junction's motor endplate. This blockage of acetylcholine receptors causes muscle weakness, often first exhibiting drooping eyelids and expanding to include overall muscle weakness and fatigue. In a cholinergic crisis, the excessive stimulation of acetylcholine receptors can cause various symptoms including decreased blood pressure and constricted pupils.